Strapping machines or strappers are in widespread use for securing bands of strap, such as plastic strapping material, around loads. One type of known strapper includes a strapping head and a drive mechanism mounted within a frame. A chute is mounted to the frame through which the strapping material is fed.
In one example, the chute is mounted proximate a work surface and the strapping head is mounted below the work surface to a horizontal portion of the chute. The strapping head is generally fixedly mounted to the strapper using fasteners, such as screws, nuts, bolts, and the like. The drive mechanism is also mounted below the work surface proximate the strapping head. In the present example, the drive mechanism urges or feeds strapping material through the strapping head and into and around the chute until the strapping material returns to the strapping head to form a strap loop around the load. After the strap loop has been formed, the drive mechanism tensions the strapping material about the load and overlapping ends of strap are secured to create a sealed, tensioned loop around the load.
In the present example, the strapping head includes a gripping assembly that grips the strap during a strapping operation and a cutting assembly that cuts the strap from a source or supply of the strapping material. In addition, the strapping head may include a sealing or weld assembly to seal the overlapping strap ends together. One example of the weld assembly includes a weld blade fixed to the strapping head that is heated or energized by an electric current flow. The weld assembly seals the overlapping strap ends together by drawing the heated weld blade between the strap ends to at least partially melt the ends and pressing the heated, melted ends together to form a weld or joint. In the present example, a transformer, which provides the current flow to the weld blade, is housed as a separate component from the strapping head and is hardwired into the strapping machine.
In order to access the strapping head mounted to the strapper, a multitude of fasteners, such as screws and bolts, must be removed. Accessing the strapping head for maintenance or repair can be time consuming and burdensome, in particular, because portions of the strapping head, such as the weld blade, may require relatively frequent inspection and servicing. Consequently, such servicing of the strapping head can lead to substantial downtime as the entire strapping machine is taken out of service for the duration of the work. In addition, skilled technicians with appropriate tools are generally required to tend to the machine during the entirety of the maintenance or repair.
Accordingly, there exists a need for a modular strapping head assembly with a heat knife that eliminates drawbacks encountered with known strapping heads. Such a modular strapping head assembly may be readily removed from and installed into a strapper as an integrated unit to minimize disassembly of the strapping machine and any downtime thereof. Further, such a modular strapping head assembly is readily installed and removed with minimal or no tools.